Support ant signing builds

.gitignore

@@ -9,3 +9,5 @@ TextSecure.iml
 out
 tests
 lint.xml
+local.properties
+ant.properties

build.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project name="TextSecure" default="help">
+
+    <property file="local.properties" />
+
+    <property file="ant.properties" />
+
+    <property environment="env" />
+    <condition property="sdk.dir" value="${env.ANDROID_HOME}">
+        <isset property="env.ANDROID_HOME" />
+    </condition>
+
+    <loadproperties srcFile="project.properties" />
+
+    <fail
+            message="sdk.dir is missing. Make sure to generate local.properties using 'android update project' or to inject it through the ANDROID_HOME environment variable."
+            unless="sdk.dir"
+    />
+
+    <import file="custom_rules.xml" optional="true" />
+
+    <!-- version-tag: 1 -->
+    <import file="${sdk.dir}/tools/ant/build.xml" />
+
+</project>